1. Field of the Invention
The present invention relates to an information processing apparatus that allows a plurality of users to commonly use a display screen, more particularly to an information processing apparatus that controls the display of an image based on coordinate information entered by the users and also controls execution of related programs.
Furthermore, the present invention relates to a method for controlling the information processing apparatus.
2. Description of the Related Art
The spread of personal computers has promoted the computerization of the office environment This includes the computerization of an employee's desk or cube, as well as other areas within the office environment such as conference rooms. A representative computerized product for a conference room is a so-called electronic conference system that includes a computerized white board. A remote-control system allowing a plurality of users to simultaneously use such an electronic conference system is already known.
Conventional conferences typically include the use of a projector that projects the screen of a laptop or notebook personal computer in addition to the use of a standard non-electronic white board. The standard non-electronic white board is generally equipped with a plurality of pens so that users can freely draw on the board.
Japanese Laid-open Patent Application No. 05-153310 proposes a system that can synchronize plotting data shared among a plurality of computerized devices connected to a network. The proposed system can execute a white board application that is simultaneously available for a plurality of users, when a screen of one computerized device is displayed on a common display apparatus and respective users have computerized devices.
Furthermore, Japanese Laid-open Patent Application No. 08-36546 proposes a system that can share display data of a particular application in addition to synchronization of plotting data shared among a plurality of computerized devices connected to a network. According to the proposed system, one user can operate on an application while other users perform plotting.
Furthermore, Japanese Laid-open Patent Application No. 2003-99196 proposes a system that can input a plurality of coordinate values to a common image display apparatus. According to the proposed system, the common image display apparatus can project screens of computerized devices. The common image display apparatus is equipped with a detecting unit that detects a plurality of coordinates, so that screens of display apparatuses of respective computerized devices can be projected as a composed image.
In this manner, simultaneous plotting is already realized by a plurality of computerized devices connected to a network.
Furthermore, according to another technique for a conference system, a plurality of computerized devices can share screen data of a host computer and plotting data on a dedicated application. Only one computerized device is allowed to remotely control the host computer to avoid interference of remote controls by a plurality of computerized devices. The proposed technique allows a plurality of computerized devices to simultaneously plot on a dedicated application.
The above systems require coordinate input apparatuses connected to the computerized devices. To realize the above-described simultaneous operations by a plurality of computerized devices, coordinate values must be input from the coordinate input apparatuses connected to the computerized devices. Plotting data must be produced based on the input data. The plotting data must be shared among the computerized devices.
Each computerized device may only function as an interface between its coordinate input apparatus and a network. In such a case, operations of respective users will interfere with each other because one computerized device is simply (i.e., without any restrictions) connected to a plurality of coordinate input apparatuses.
More specifically, a computerized device outputs plotting data to a display apparatus that displays a common screen. When the computerized device is simply connected to a plurality of coordinate input apparatuses, a plurality of users may simultaneously input coordinate data via a plurality of coordinate input apparatuses. Interference of operations typically occurs in such an arrangement.
Occurrence of interference is due to the fact that, according to a conventional window system, a focused window is selected as an operation target among a plurality of windows. In other words, even if one computerized device is connected to a plurality of coordinate input apparatuses, the computerized device can operate for only one target.
Thus, when coordinate values are simultaneously entered from a plurality of coordinate input apparatuses, conflict occurs to get an operation target. In other words, the operation of the computerized device interrupts every time the coordinate input apparatus is switched.
For example, one computerized device can be equipped with a mouse and a tablet, each serving as a pointing device, so that users A and B can operate the computerized device. User A may operate the mouse to draw a line on a plotting application screen (or window), while user B may access a browser to enjoy net surfing.
Under such a situation, the line on the plotting application screen may be unintentionally drawn to a point whose coordinates are instructed by the other user. Thus, the operation of user B obstructs the operation of user A.
To solve the above drawbacks, a conventionally proposed method gives a priority to one apparatus if it entered the coordinate data earlier than others, and designates it as an operable coordinate input apparatus. However, according to the method, only one coordinate input apparatus is allowed to input coordinate data. When one computerized device simultaneously receives coordinate values from a plurality of coordinate input apparatuses, the computerized device cannot realize simultaneous operations using a plurality of coordinate input apparatuses.
Furthermore, the simultaneous plotting can be realized by a dedicated common screen display apparatus that is equipped with a plurality of coordinate input apparatuses and processing units. However, according to such a method, the computerized device currently displaying an image on the common screen display apparatus cannot be operated by a coordinate input apparatus equipped in the common screen display apparatus.
Therefore, a user must switch the coordinate input apparatus to change the operation of the computerized device from the simultaneous plotting to another operation.